초록

A process and corresponding apparatus for dehydrating gas, especially natural gas. The process includes an absorption step and a membrane pervaporation step to regenerate the liquid sorbent.

대표청구항 ▼

We claim: 1. Apparatus for carrying out a dehydration process, comprising the following elements: (a) an absorber, having a wet gas inlet line, a dehydrated gas outlet line, a liquid desiccant inlet line and a spent liquid desiccant outlet line, and being adapted to bring wet gas into water-partiti

We claim: 1. Apparatus for carrying out a dehydration process, comprising the following elements: (a) an absorber, having a wet gas inlet line, a dehydrated gas outlet line, a liquid desiccant inlet line and a spent liquid desiccant outlet line, and being adapted to bring wet gas into water-partitioning contact with a liquid desiccant; (b) a membrane separation unit, having a feed inlet line, a feed outlet line, and a permeate outlet line, and containing an inorganic membrane having a feed side and a permeate side, and characterized by the ability to provide pervaporation separation factors of at least about 100 in favor of water over liquid desiccant and in favor of water over benzene when used to treat a liquid desiccant stream containing about 5 wt % water and 1 wt % benzene at 200째 C.; (c) a first connection line connecting the membrane separation unit feed inlet line and the absorber spent liquid desiccant outlet line, so that spent liquid desiccant may pass out of the absorber and into the membrane separation unit; (d) a second connection line connecting the membrane separation unit feed outlet line and the liquid desiccant inlet line, so that regenerated liquid desiccant may pass out of the membrane separation unit and into the absorber; (e) a heater positioned in the first connection line between the absorber and the membrane separation unit to enable spent liquid desiccant to be heated before entering the membrane separation unit. 2. The apparatus of claim 1, wherein the liquid desiccant is glycol. 3. The apparatus of claim 2, wherein the glycol is selected from the group consisting of monoethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol. 4. The apparatus of claim 2, wherein the liquid desiccant is triethylene glycol. 5. The apparatus of claim 1, further comprising a permeate sweep gas inlet line to the membrane separation unit, to provide a flow of sweep gas across the permeate side of the inorganic membrane. 6. The apparatus of claim 5, further comprising a pump positioned in the permeate sweep gas inlet line. 7. The apparatus of claim 1, wherein the inorganic membrane comprises a silica membrane. 8. The apparatus of claim 1, wherein the inorganic membrane comprises a zeolite membrane. 9. The apparatus of claim 1, wherein the absorber comprises an absorption column. 10. The apparatus of claim 1, wherein the absorber comprises a membrane contactor. 11. The apparatus of claim 1, wherein the heater comprises a heat exchanger adapted to bring a spent liquid desiccant stream from the spent liquid desiccant outlet line and a regenerated liquid desiccant stream from the membrane separation unit feed outlet line into heat-exchanging contact. 12. The apparatus of claim 1, wherein the heater comprises a gas-fired heater. 13. The apparatus of claim 1, wherein the heater comprises a steam heater. 14. The apparatus of claim 1, further comprising a cooler positioned in the second connection line between the membrane separation unit and the absorber to enable regenerated liquid desiccant to be cooled before entering the absorber. 15. The apparatus of claim 14, wherein the cooler comprises a heat exchanger adapted to bring a regenerated liquid desiccant stream from the membrane separation unit feed outlet line and a spent liquid desiccant stream from the spent liquid desiccant outlet line into heat-exchanging contact. 16. The apparatus of claim 14, wherein the cooler comprises an air cooler. 17. The apparatus of claim 14, wherein the cooler comprises liquid refrigeration. 18. The apparatus of claim 1, wherein the absorber, the membrane separation unit, and the first and second connection lines form a liquid desiccant circulation loop, and further comprising a purge line in the liquid desiccant circulation loop for purging liquid desiccant from the liquid desiccant circulation loop. 19. The apparatus of claim 1, wherein the absorber, the membrane separation unit, and the first and second connection lines form a liquid desiccant circulation loop, and further comprising a fresh liquid desiccant inlet line in the liquid desiccant circulation loop for introducing liquid desiccant into the liquid desiccant circulation loop. 20. The apparatus of claim 1, further comprising a pump positioned in the second connection line between the membrane separation unit and the absorber to pump the regenerated liquid desiccant stream from the membrane separation unit feed outlet line to the liquid desiccant inlet line of the absorber.